Alberucci, A.A.AlberucciJisha, C.P.C.P.JishaNolte, S.S.Nolte2022-03-062022-03-062018https://publica.fraunhofer.de/handle/publica/25862410.1364/OL.43.004949We discuss the effective photonic potential for TM waves in inhomogeneous isotropic media. The model provides an easy and intuitive comprehension of form birefringence, paving the way for a new approach on the design of graded-index optical waveguides on nanometric scales. We investigate the application to nanophotonic devices, including integrated nanoscale wave plates and slot waveguides.en620journal article